You probably already know that the prominent writing on the right says 祈武運長久 (pray for good luck in battle).
The bit under that might be the name of the recipient, and might be 為折戸囗囗 (For Oribe -- ) (I can't read the given name).
But the writing is very poor, and particularly the sloppy writing for the person's name would hardly be acceptable on an item like this. The rest of the names around the red disk are signatures. There is no date or location written on this.
It isn't unusual for flags not to have dates or locations on them. The lack of these things doesn't prove the flag is fake. On the other hand, a flag with a clearly written name, a location, and a date, can be traced back to the original owner, and depending on the location it can be validated pretty easily. For example if the flag has the name of a school on it, and the principal has signed the flag - or if a factory's workers have signed the flag, and the factory manager/president put his name on it, it can be partially authenticated just using a search engine. But a flag with none of these marks makes it difficult or impossible to trace, and therefore I am always suspicious of them.
